【作者】 罗清威；

【导师】 王梅； 樊占国；

【作者基本信息】 东北大学 ， 环境科学， 2009， 硕士

【摘要】 高温超导材料以其独特的特性,将成为21世纪最具有发展前途的新型材料。要想制备出高质量的超导带材,缓冲层及YBCO超导层的制备技术是极其关键的。金属有机沉积（MOD）法因不需要真空环境,制备的薄膜厚度均匀,设备简单,成本低,而被广泛应用。本论文采用MOD法在双轴织构的镍钨合金（Ni-5at.%W）基带上制备La_1-xSr_xTiO₃导电缓冲层薄膜及YBCO超导薄膜,同时也探讨了采用磁控溅射法在Ni-W基底上制备银薄膜的技术。采用MOD法在Ni-W基底上沉积了La_1-xSr_xTiO₃（LSTO）薄膜,讨论不同热处理温度和热处理时间对薄膜生长和性质的影响。结果表明:在相同条件下,900℃时LSTO衍射峰的强度增强;热处理时间对LSTO薄膜的取向和表面形貌影响不大。磁控溅射法在Ni-W基底上制备Ag缓冲层的实验中,讨论了不同热处理温度及不同降温速率对薄膜取向的影响。实验初步发现:随着热处理温度的提高,银的（200）取向逐步增强,本实验所确定的最佳热处理温度为900℃。较慢的降温速率条件下制备的银薄膜（200）取向的晶粒择优生长。在采用无氟的MOD法在LSTO/Ni-W结构上制备YBCO超导层的实验中,研究了前驱液的稳定性、热处理温度和升温速率对薄膜性能的影响。经实验初步发现:本实验所配置的前驱液是比较稳定的（至少一个月以内）。850℃下制备的薄膜织构得到优化,取向进一步改善。但是衍射图谱中存在其它取向的衍射峰,因而薄膜电阻较大,不具有超导电性。不同的升温速率对薄膜性能的影响不大,相对较慢的升温速率对YBCO（00l）取向的形成有利。在无氟的MOD法在Ag/Ni-W结构上制备YBCO超导薄膜的实验中,研究了银的取向对YBCO薄膜取向和表面形貌的影响。实验初步表明,在其他条件不变的情况下,银（200）择优的薄膜上生长的YBCO的取向趋于优化,其它取向的衍射峰被弱化。更多还原

【Abstract】 Due to its unique features,High-temperature superconducting materials will become the most promising new materials in the 21st century.To prepare high-quality superconduting tapes,the buffer layer and YBCO superconducting layer preparation technology is extremely crucial.Metal-organic deposition（MOD） method is widely used as it does not need vacuum environment,and can prepare a film with uniform thickness with simple equipment at low cost.In this thesis, La_1-xSr_xTiO₃（LSTO）buffer layer and YBCO superconducting layer were deposited on the rolling-assisted biaxially textured substrates（RABiTS）Ni-5at%W alloy with the Metal-organic deposition（MOD）method.Then the techniques of preparing Ag film buffer layer on Ni-W tapes were studied.La_1-xSr_xTiO₃（LSTO） buffer was prepared with Metal-organic deposition（MOD） method.The effects of annealed temperatures and annealed times on the properties of the films were investigated.The results showed that under the same conditions, the intensity of LSTO diffraction peaks were enhanced when annealed at 900℃,and annealed times have little effect on the film orientation and surface morphology.Ag conductive buffer was prepared on Ni-W substrate by Magnetron Sputtering method.The effects of annealed temperature and cooling rate on the film orientation were discussed in this paper.The experiment preliminary found that Ag（200） orientation was gradually strengthened with the heat treatment temperature increased. In the experiment it was determined that the best annealed temperature is 900℃.The Ag film（200） orientation is preferred under the conditions of slower cooling rate.In the experiment YBCO superconducting layer was prepared on the LSTO/ Ni-W structure by Fluorine-free MOD method.The effects of the stability of precursor solution,annealing temperature and heating-up rate on the properties of the films were investigated.The results showed that the precursor solution confected in the experiment is relatively stable（at least within one month）.The texture and orientation of the film annealed at 850℃were optimized and improved.However, some other orientations’ diffraction peaks exist in the diffraction pattern,therefore thin-film resistance get larger,consequently does not have superconductivity.With different heating-up rate annealed at 850℃,consequently the YBCO film hardly changed.The relatively slower heating-up rate was benefit the formation of YBCO（00l） orientation.In the experiment of prepare YBCO superconducting film on the Ag/Ni-W structure by Fluorine-free MOD method,the effects of the orientation of Ag film on the orientation and surface morphology of the YBCO films were studied.The experiment preliminary found that if the other conditions remain unchanged,the YBCO film deposited on Ag（200） orientation’s film tend to optimized,and the diffraction peak intensity of other impurity were weakened.更多还原